Adjustable rear mount for machine guns



J n 1951 P. E. PETERSON ADJUSTABLE REAR MOUNT FOR MACHINE GUNS FiledJuly 21, 1944 INVENTOR. Paul F Peterson A iiorzwy Patented Jan. 9, i951V. UNITED STATES PATENT o rrics PauliF. PetersomLos Angeles, O'alifi,'assignor to North American Aviation, Inc.

Application-Jilly 21, 1944-, Serial Ni"54 5,941

16' Claims.

The present invention relates to improvements in adjustable rearmountings for fixed machine gunsof a type particularly adaptable foraircraft installations.

It is an object of the present invention to provide amount suitable forthe foregoing, purpose, which is generally compact in all dimensions andparticularly in the vertical height whereby a minimum amount ofclearance is required on an installation. In current gun placementdesigns in aircraft wherein a plurality of guns are included within thewing of a ship, difiiculties are frequently encountered owingto the verylimited amount of clearance within the wing structure, especially in theoutboard portion of the extremely thin wings employed on fighter ships.It accordingly becomes of considerable importance to provide asatisfactory mounting means including provision for adjustment ofthe gunin both azimuth and elevation and yet requiring aminimum amount of.clearance between the lower skin-of the wing andlthe bottom of the gun.It is a further object of this invention to pro-. vide adjustment meansfor a gun. mount as above described which are readily accessible andsimple of operation. Previous designs have frequently required thatadjustments be made from the underside of the wing. Such an arrangementhas numerous disadvantages; such :as. generally re-- quiring two personsin order to perform the operation satisfactorily, one ion the wing todirect the operation, while a second operates the adjusting meansbeneath the wing. Such an arrangement also "generally resulted inaportion of the adjusting means projecting through the lower wingsurface andinto the airstream, or a suitable access door was. required.The present arrangeme-nt is completely housed, accessible from above,can-be readily adjusted by one man, requires,v no special tools and is.completely selflocking immediately uponcompletion. of the requiredadjustment.

It is a furtherobject of: the invention to provide a rear gun mountwhich will improve the performance and accuracy of the gun duringfiring. To this end, the longitudinal recoil forces are not transmittedto the rearmount since the rear clamp is free-floating andself-aligning. The longitudinal recoil forces are entirely "taken by thefront mount and the rear mount serves only to position the gun, i. e.,takes loads only in the vertical or transverse horizontal plane. Aconsiderable improvement in the dispersion pattern of the gunduringfiring is thereby effected.

Astill further object of the present invention is the provision of anadjustable rear gun mount including a quickly releasable securing meanswhich maybe attached to the gun at any convenient point along thelower-side of the rear portion of the gun. ;This -mount may also bereadilyinstalled-in such a-manner as to-support 2 the gun from above andmay be attached to the upper. side of the rear portion of, the gun withequal facility.

Still further objects of the present invention are the provision ofanadjustable rear-gun mount of simple design and rugged constructionwhich lends itself readily to production, being inexpensive to build andhaving relatively few parts, providing a full range of adjustments whichmay be'quickly and easily madeand are automati cally secured byself-locking provisions.

Like reference characters designate similar parts in the several viewsof the drawings, in which:

Fig. 1 is-a top plan view of the rear mount;

Fig. 2 is an end elevation of the mount showing the gun in position;

Fig. 3 is a side elevation of the mount taken on line 3-3 of Fig. 1,indicating the gun in phantom;

Fig. 4 is a frag-mentarysection takenon 1' 4-4 -of Fig. 2; and

:Fig; 5 is a side elevation of a machine :gun mounted in accordance withthe invention.

As an example of. one-formin which the in-- vention may beembodied, Ihave shown in thedrawing a-machine gun, indicated generally at A,mounted on a supporting-structure 4 (suchias a frame member "of amilitary airplane). The gun Ads of :a type (such as 'disclosecl inthepatent to; Browning No. 1,628,226) including a barrel Tb and a casingc, with-conventional recoil absorbing mechanism interposed between thebarrel 'b and the casing c. The casing c is mounted on the support '4 bymeans'of a front mount d,v which 'formsa relatively rigid, recoiltransmitting pivotal' connection between the'casing 'c and the :supportl, and a rear mount 6 which provides whati maybe termed a longitudinallyfloating-connec-. tion between the'casing' c and the support '4 so astoofi'er no resistance to the recoil, .but which is adapted "to"restrain the rear end of the gun against movements transverse to thelongitudinal axis of the gun, either in a vertical or a horizontaldirection.

The rear mounting unit e, which includesfur- 4 ther detailed features ofthe invention, comprises a bracket 1 having parallel side flanges 2-3whereby the mount is attached to'the, supporting structure 4 as by bolts5-5, 6-45. An adjustable member 1 whih comprises a pair of 'rearwardlyto right'or-left by the-rotationpof'shaft ll. Gun,

3 engaging means are supported upon the block. A hexagonal head I4 isprovided at one end of the shaft ll whereby the required rotation may bereadily accomplished in order to secure the desired adjustment of thegun IS in azimuth. A spring detent I6 is arranged to bear against theflat surfaces of the hexagonal head l4, thereby providing for theretention of the adjustment. The application of a turning force ofsufficient moment to rotate the shaft may be readily obtained with asuitable tool, the locking spring deflecting momentarily to permit thepassage of the corners of the head l4.

The arm 9, extending forwardly and upwardly, is slotted at I! to receivea bearing block I8 which is journalled in the bifurcated end portion ofthe arm, and cooperatively engages an adjusting screw I9. The lowerextremity of this screw is journalled in a slotted plug inserted withina boss 2| which is slotted at 22 to permit the selfalignment of theassembly throughout the full range of adjustment. Rotation of theadjusting screw l9 in engagement with the bearing block l8 will securethe vertical adjustment of the gun by virtue of the entire adjustableunit 189 being pivoted about the pin l0. A spring detent 23 secured tothe frame at 24 bears against a hexagonal portion 25 adjacent the lowerextremity of the adjusting screw l9 whereby the desired adjustment willbe retained.

The block [3, which carries the gun engaging means, is provided with anupwardly extending lug 26 received within a recess in the yoke 21 and ispivotally connected thereto by a short pin 28. The pin is secured to thelug 26 at 29. The lug 26 is positioned in spaced relationship to thesides of the opening provided in the yoke 21 and a pair of resilientwashers 30-30 are inserted therebetween. This provides a free-floatingarrangement wherein the yoke 21 is relatively unrestrained and thereforemay be permitted to move axially upon the pin 28, the resilient washersserving as buffers. This prevents longitudinal recoil forces of the gunfrom being transmitted to the mount and the supporting structure,thereby preventing a restraining action from occurring at the rear mountwhereby the dispersion pattern of the gun is considerably improved.

The floating arrangement provided between the block l3 and the yoke 21by the pin 28 also allows the gun engaging clamp to become self-aligningby way of rotation of the yoke on the pin. This feature is advantageousin that minor misalignments which may be encountered between the variousportions of the gun mount and supporting structure are readilyaccommodated.

The yoke 21 is provided with quickly releasable clamping means forengaging the gun and securing it to the mount. This means comprises afixed jaw 3| and an opposing movable jaw 32 pivoted at 32a to the yoke21, together with an adjusting screw 33, threaded through a boss 34 onthe yoke 21, bearing against the movable jaw 32, and having a wing head35 for engagement by the fingers of an operator. Means for retaining therequired clamping adjustment are also provided, comprising a resilientmember 36 apertured at 31 to engage the hexagonal portion 38 of the head35. The resilient member, secured to the yoke at 39, may be deflectedtoward the yoke to be disengaged from the hexagonal portion of the head35 to allow the adjusting screw to be rotated and release thetensi-oning means for free rotation and when released will spring backinto locking engagement with the hexagonal portion 38.

This quickly releasable clamp arrangement provides a means whereby thegun may be engaged at any convenient point along the length of the loweredge. Alternatively the entire mount may be installed in an invertedposition whereupon the clamping means will engage the correspondingportion of the upper edge of the gun case as at 40. This permits. agreater degree of latitude in designing such installations as well asfacilitating the actual servicing operation, requiring removal andreplacement of the guns. Servicing operations are further simplified bythe provision of a light torque spring 4| bearing against the movablejaw 32 and tending to urge it constantly against the tensioning screw 33whereby the clamping means is held in open position to receive the gun.As a still further aid, a lug 42 is provided on the block l3 and aspring 43 is attached to the supporting structure as at 44 whereby theentire unit l321 is held erect and in proper gun engaging attitude,avoiding the possibility of difiiculties being encountered by virtue ofthe yoke falling over during the placing of the gun.

I find that by employing a recoil transmitting forward mount incombination with a longitudinally floating but transversely restrainingrear mount, that the dispersion firing pattern of the gun is verydefinitely improved. Where an attempt is made to restrain recoil throughthe rear mount as well as the front mount, the recoil induced dispersioneffects upon the gun are more pronounced and the dispersion patternbecomes more irregular.

It may be noted that the upper portions of the lever 9 and adjustingscrew l9 project upwardly beyond the bottom of the gun casing I5, in aplane at one side of thegun casing, while the bracket I, the bearingportion of the lever 9, and the clamp 21 are largely disposed betweenthe lower side of the gun and the support 4. The head of the screw l9projects upwardly at one side of the gun so as to provide for easyaccess for adjusting purposes.

I claim as my invention:

1. An adjustable gun mount comprisingabracket for attachment to asupport, a clamp adapted to embrace and engage the lower portion of agun casing, said clamp including a pair of spaced portions havingaligned bearing apertures, a pin extended through said apertures andsupporting said clamp for sliding movement in the direction parallel tothe longitudinal axis of the gun, a lever having at one end an upwardlyextending lug received between said spaced clamp portions and attachedto and supporting the intermediate portion of said pin, cushioning meansinterposed between said lug and the respective spaced portions of saidclamps, for yieldingly opposing said sliding movement, means pivoting anintermediate portion of said lever upon said bracket on a horizontalaxis transverse to said longitudinal axis for adjusting movement in avertical plane, and an adjustin screw forming an adjustable connectionbetween the other end of said lever and said bracket for effecting saidadjustment in a vertical plane.

2. A gun mount as defined in claim 1, wherein said adjusting screwextends upwardly and rearwardly and has at its upper end a head forengagement by an adjusting tool.

3. A mount for floatingly attaching a portion of a gun to a supportcomprising a lever, means for adjustably connecting said lever to saidsupport. means for holding said. lever in adjusted position, and meansfixed to the gun and carried by said lever means for carrying said gunwith.

5. A device as recited in claim 4 and further including buffer meansinterposed between said pin and yoke.

6. A mount'for floatingly attaching the rear portion of a gun to asupport comprising interengaging means one of which is to be fixed tothe support and the other of which is fixed to the gun and carried bythe first named means with freedom for sliding movement in the directionof the longitudinal axis of the gun and rotative movement in a directiontransverse thereto.

7. A device as recited in claim 6 and further including bufier meansinterposed between said interengaging means.

8. A mount for floatingly attaching aportion of a gun to a supportcomprising a pin to be fixed to the support and extending substantiallylongitudinally of the gun, a yoke fixed to the gun and mounted on thepin with freedom for rotative and sliding movement, and buffer meansbetween the pin and yoke. I

9. A mount for floatingly attaching a portion of a gun to a supportcomprising a lever, means for adjustably connecting said lever to saidsupport, means for holding said lever in adjusted position, and meansfixed to the gun and carried by said lever means for carrying said gunwith freedom for movement in the direction of its longitudinal axis androtative movement in a direction transverse thereto, and buffer meansbetween the lever means and the means fixed to the gun.

10. A mount for fioatingly attaching a portion of a gun to a support foruse in a mounting arrangement wherein another portion of the gun isrelatively unyieldingly attached to the support, comprisinginterconnected elements one of which is to be adjustably fixed to thesupport and the other of which is fixed to the gun and carried by thefirst named element with freedom for movement in the direction of thelongitudinal axisof the gun, and buffer means between the interconnectedelements.

11. A mount for floatingly attaching a portion of a gun to a support foruse in a mounting arrangement wherein another portion of the gun isrelatively unyieldingly attached to the support, comprisinginterconnected elements one of which is to be adjustably fixed to thesupport and the other of which is fixed to the gun and carried by thefirst named element with fr edom for move support and the other of whichis fixed to the gun and carriedby the first named element with freedomfor yielding movement in the direction of. the long tudinal axis of thegun and rotational movementin a direction generally transverse tothejlongitudinal axis of the gun, and means 01 restraining said otherelement against movement in vertical and transverse horizontaldirections.

13. A mount for floatingly attaching :a portion of a gun to a supportcomprising vertical adjustable means carried by the support, laterallyadjustable means carried by said vertical adjustable means, and yokemeans attached to said gun and to said laterally adjustable means withfreedom for rotative and horizontal longitudinal movements butrestrained against lateral movements in horizontal and verticaldirections.

14. An adjustable gun mount comprising a bracket for attachment to asupport, said bracket being interposed beneath the underside of the gunand said support, means for attachment to said gun, a lever on whichsaid means is pivotally mounted, said lever being fulcrumed on saidbracket for movement such as to effect adjustment of said gun, and anadjusting screw acting between said lever and said bracket and adaptedto effect said adjusting movement of said lever, said adjusting screwand the upper portion of said lever being disposed at one side of thegun with the head of the screw projecting upwardly.

15. In a mounting arrangement for attaching a gun to a support,relativelyunyielding means for attaching one portion of the gun to thesupport; and means for fioatingly attaching another portion of the gunto the support comprising interengaging means, one of which is to befixed to the support and the other of which is fixed to the gun andcarried by the first named means for freedom of sliding movement in thedirection of the longitudinal axis of the gun and rotative movement in adirection transverse thereto.

16. A mount for adjustably attaching a gun to a support comprisingbracket means for attachment to said support, a lever fulcrumed on saidbracket means for movement with respect thereto, means for holding saidlever in adjusted position, gun engaging means carried by said lever andadjustable in a, direction generally at right angles to the direction ofmovement of said lever,

and means fixed to said gun and carried by said lever for carrying saidgun with freedom for movement in the direction of its longitudinal axisand rotative movement in a direction transverse thereto.

PAUL F. PETERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,594,365 Houbroe Aug. 3, 19261,628,226 Browning May 10, 1927 2,076,256 Swalm et al. 1 Apr. 6, 19372,293,069 McNeil et al Aug. 18, 1942 2,326,904 Trimbach Aug. 17, 19432,334,984 Berlin et a1 Nov. 23, 1943 2,335,835 Zietlow Nov. 30,- 19432,364,509 Bertran et a1 Dec. 5, 1944 2,380,773 McMullen July 31, 19452,385,218 Martin Sept. 18, 1945 FOREIGN PATENTS Number Country 7 Date25,119 Austria July 25, 1906 324.308 Germany Aug. 26, 1920 483,847 GreatBritain Apr. 12, 1938 491,353 Great Britain Aug. 31, 1938 865,951

France Mar. 24, 1941

